Trends in Integrated Motor Drives

The trend toward distributing automation and motion control devices is enabling the move to modular machine designs, and has become a large part of the underlying value proposition for integrated motor drives that incorporate servo technology.

The result is that more automation suppliers are introducing integrated motor drive offerings and there is a push to adding advanced solutions. New products for easily interfacing remote distributed I/O, the ability to execute repetitive motion sequences in firmware, and safety on a per-axis basis are making systems more potent than ever before.

Achieving greater modularity in machine building is an overall trend among automation machine builders. Customers are demanding greater flexibility and versatility of the equipment they are building with the shift away from machines being built to stock and sold off-the-shelf. Many machines are now designed and built to order, and the challenge has been for the machine builder to come up with modular designs that can be combined in different configurations, for differing requirements.

Modular design is increasingly an answer to the need for OEM machinery builders to create custom machinery. And while machinery builders have done a good job of doing this mechanically with machine sections that can be reused and reconfigured, the electronics in these types of systems has always been a difficult problem. The typical approach in the past has been a central electrical enclosure, with ample additional space in the control cabinet for any possible options even if individual systems often didn't require them.

A modular control architecture utilizing remote I/O, drives, and cameras with only some base components remaining in a central enclosure is shown using the example of a modular packaging machine.

Muehlfellner told us:

Another important trend in modular design is the adoption of distributed I/O in both the IP67 format and now with motor-mounted drives or machine-mounted drives that are installed near a motor. Getting the power conversion out of the enclosure and out onto the machine is an advantage. This is a logical continuation from distributed I/O to drives, and extends what we have seen happening with I/O for several years now.

This decentralized architecture also benefits from increasing use of a single cable connection for all of the individual modules of the modular machine. As machine modules are built mechanically, the electronic components (motors, integrated drives, distributed I/O, safety devices) can all be mounted on the machine close to the actuation point where the motion is happening.

Connecting one machine module to the next can be accomplished using a single hybrid cable that carries the power and control voltages, communication, and safety signals. The modular approach has been advancing step-by-step from mechanical modular design, to electrical modular design using a single connecting cable, and following through on the software side with modular engineering process tools.

Muehlfellner said motor-integrated drives make the most sense on machines with a larger footprint that implement a higher number of servo axes (four axes and up). Packaging, converting, and paper handling are good examples of the type of equipment that would benefit from this approach. The technology is available in a limited power range (1kW to 5kW) although B&R sees that range expanding, in the future, in both directions.

Chuck, A primary reason to separate motors and drives in the past has been packaging the two together, and especially the ability of the drive to handle heat. There is significant technology involved in mounting the drive to the top of the motor, but it is still an issue as motor/drive combos go up in torque (with resulting increases in heat).

2 reasons; first, motors and drive electronics are both heat producing systems. In order to combine them you have to derate the assembly to prevent damage, and second, motors are designed by mechanical engineers, motor drive circuits are designed by electronics engineers. The two disciplines and attending manufacturing processes are completely different.

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